Color image forming apparatuses well known in the art, such as that disclosed in U.S. Pat. No. 6,708,011 (corresponding to Japanese Patent Application Publication No. 2003-15378), have been configured with a cartridge for integrally holding four photosensitive members and their peripheral components, the cartridge being detachably mounted in the body of the apparatus by sliding.
With this type of color image forming apparatus, it is necessary to position the cartridge for the photosensitive members accurately relative to the body of the apparatus. Since the cartridge is detachably mounted in the body of the image forming apparatus while an exposure unit is fixed to the body, the cartridge for the photosensitive members must be accurately positioned in the body of the apparatus when mounted therein in order to position the photosensitive members accurately relative to the exposure unit.
To achieve this, positioning members have been provided in the body of the conventional apparatus for contacting and positioning the cartridge accommodating the photosensitive members. However, since the cartridge is detachably mounted in the body of the apparatus by sliding, the cartridge collides forcibly with the positioning members when vigorously slid into the body of the apparatus. The impact of such collisions may cause damage to the positioning members and/or parts of the cartridge that contact the positioning members.